That "Simple & Direct" is also "Thorough and
Scholarly" is manifest in its CONTENTS page:
Introduction
I. DICTION, or Which Words to Use
II. LINKING, or What to Put Next
III. TONE AND TUNE, or What Impression Will It Make
IV. MEANING, or What Do I Want to Say?
V. COMPOSITION, or How Does It Hang Together
VI. REVISION, or What Have I Actually Said?
Hints Toward Improving the Quoted Sentences
Index of Words, Topics, and Authors

For information on Barzun see e.g.:
(a) the Wikipedia entry at <http://bit.ly/Yxp4yw>;
(b) the eulogy by Rothstein (2012) at
<http://nyti.ms/YIPAY1>;
(c) the eulogy by Epstein (2012) at
<http://on.wsj.com/ZU4xoR>;

(d) the interview by
Gathman (2000) at <http://bit.ly/17dQaje>;
(e) the biography by Murray (2011) at
<http://amzn.to/120G3rS>;

"[Jacques Barzun] wrote in a flawless and magisterial manner on a
vast array of subjects: Darwin, Marx, Wagner, Berlioz, William James,
French verse, English prose composition, university teaching,
detective fiction, the state of intellectual life, and finally,
published when he was 93, his magnum opus, 'From Dawn to Decadence:
500 Years of Western Cultural Life, 1500 to the Present.' None of this
writing seemed motivated by his desire to advance his career; all of
it derived from genuine intellectual passion."
- Epstein (2012)

REFERENCES [URL's
shortened by <http://bit.ly/> and accessed on 12 May
2013.]

Hake, R.R. 2013.
"How To Write Good - ADDENDUM #2," online on the OPEN!
Net-Gold archives at <http://yhoo.it/11tJ4WK>. Post of 11 May
2013 14:56:55-0700. The abstract and link to the complete post are
being transmitted to several discussion lists and are on my blog
"Hake'sEdStuff" at <http://bit.ly/10OgckH> with a
provision for comments.